U.S. patent number 7,163,159 [Application Number 10/618,713] was granted by the patent office on 2007-01-16 for fuel injector including a compound angle orifice disc.
This patent grant is currently assigned to Siemens VDO Automotive Corporation. Invention is credited to J. Michael Joseph.
United States Patent |
7,163,159 |
Joseph |
January 16, 2007 |
Fuel injector including a compound angle orifice disc
Abstract
A fuel injector includes a metering orifice disc. The metering
orifice disc includes a peripheral portion, a central portion, and
an orifice. The peripheral portion is with respect to a
longitudinal axis and extends parallel to a base plane. The
peripheral portion bounds the central portion. The central portion
includes a facet that extends parallel to a plane that is oblique
with respect to the base plane. The orifice penetrates the facet
and extends along an orifice axis that is oblique with respect to
the plane. As such, the orientation of the orifice with respect to
the longitudinal axis is defined by a combination of (1) a first
relationship of the plane with respect to the base plane, and (2) a
second relationship of the orifice axis with respect to the plane.
A method of forming a multi-facetted dimple for the metering
orifice disc is also described.
Inventors: |
Joseph; J. Michael (Newport
News, VA) |
Assignee: |
Siemens VDO Automotive
Corporation (Auburn Hills, MI)
|
Family
ID: |
34062450 |
Appl.
No.: |
10/618,713 |
Filed: |
July 15, 2003 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20050011973 A1 |
Jan 20, 2005 |
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Current U.S.
Class: |
239/5; 239/494;
239/497; 239/533.12; 239/552; 239/585.5; 239/596 |
Current CPC
Class: |
F02M
51/0671 (20130101); F02M 61/1853 (20130101) |
Current International
Class: |
F02M
61/00 (20060101) |
Field of
Search: |
;239/491,494,497,533.12,552,584,585.1,585.4,585.5,596,1,5
;29/890.132,890.142,890.143 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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10034293 |
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Jul 2001 |
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DE |
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1118767 |
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Oct 2001 |
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EP |
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3529223121 |
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Dec 1984 |
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JP |
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60137529 |
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Jul 1985 |
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JP |
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352032192 |
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Mar 1997 |
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JP |
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Other References
PCT International Search Report filed Jun. 18, 2004
(PCT/US2004/0195047) and date of mailing Nov. 5, 2004. cited by
other.
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Primary Examiner: Ganey; Steven J.
Claims
I claim:
1. A fuel injector for metering, atomizing, and spray targeting
fuel, the fuel injector comprising: a seat including a passage
extending along a longitudinal axis; a movable member cooperating
with the seat to permit and prevent a flow of fuel through the
passage; and a metering orifice disc including: first and second
surfaces, the first surface confronting the seat, and the second
surface facing opposite the first surface; a peripheral portion
with respect to the longitudinal axis, the peripheral portion
extending parallel to a base plane, and the base plane being
generally orthogonal with respect to the longitudinal axis, the
base plane comprising an interface of the seat and a peripheral
portion of the first surface; a central portion with respect to the
longitudinal axis, the central portion being bounded by the
peripheral portion and including a first facet extending parallel
to a first plane, the first facet being coupled to the peripheral
portion along a first peripheral segment, and the first plane being
oblique with respect to the base plane; and a first orifice
penetrating the first facet and being defined by a first wall
coupling the first and second surfaces, the first orifice extending
along a first orifice axis, and the first orifice axis being
oblique with respect to the first plane such that an orientation of
the first orifice with respect to the longitudinal axis is defined
by a combination of a first relationship of the first plane with
respect to the base plane and a second relationship of the first
orifice axis with respect to the first plane, wherein the central
portion of the first surface comprises an apex and a perpendicular
height of the apex with respect to the base plane, and there is a
generally direct correlation between the apex height and the
orientation of the first orifice with respect to the longitudinal
axis.
2. The fuel injector according to claim 1, wherein the first
surface is generally parallel to the second surface.
3. The fuel injector according to claim 1, wherein the first
surface and second surface comprise a planar surface extending away
from the seat and oblique to the longitudinal axis.
4. The fuel injector according to claim 1, wherein the first
surface and second surface comprise a planar surface extending
towards the seat and oblique to the longitudinal axis.
5. The fuel injector according to claim 3, wherein a sac volume is
defined by the first surface of the metering orifice disc and the
member cooperating with the seat to prevent the flow of fuel, and
there is a generally direct correlation between the sac volume and
the orientation of the first orifice with respect to the
longitudinal axis.
6. A metering orifice disc for a fuel injector including a passage
extending along a longitudinal axis between an inlet and an outlet,
a closure member reciprocating along the longitudinal axis, and a
seat proximate the outlet and cooperating with the closure member
to permit and prevent a flow of fuel through the passage, the
metering orifice disc comprising: a member including first and
second generally parallel surfaces, the first surface being adapted
to generally confront the valve seat, and the second surface facing
opposite the first surface, the member including: a peripheral
portion with respect to the longitudinal axis, the peripheral
portion extending parallel to a base plane, and the base plane
being generally orthogonal with respect to the longitudinal axis; a
central portion with respect to the longitudinal axis, the central
portion being bounded by the peripheral portion and including a
first facet extending parallel to a first plane, the first facet
being coupled to the peripheral portion along a first peripheral
segment, and the first plane being oblique with respect to the base
plane; and a first orifice penetrating the first facet and being
defined by a first wall coupling the first and second surfaces, the
first orifice extending along a first orifice axis, and the first
orifice axis being oblique with respect to the first plane such
that an orientation of the first orifice with respect to the
longitudinal axis is defined by a combination of a first
relationship of the first plane with respect to the base plane and
a second relationship of the first orifice axis with respect to the
first plane, wherein the central portion of the first surface
comprises an apex and a perpendicular height of the apex with
respect to the base plane, and there is a generally direct
correlation between the apex height and the orientation of the
first orifice with respect to the longitudinal axis.
7. The metering orifice disc according to claim 6, wherein the
central portion of the member comprises a second facet extending
parallel to a second plane, the second facet being coupled to the
peripheral portion along a second peripheral segment, and the
second plane being oblique with respect to the base plane.
8. The metering orifice disc according to claim 7, wherein the
second plane being oblique with respect to the first plane.
9. The metering orifice disc according to claim 8, wherein the
second facet is coupled to the first facet along a first central
segment.
10. The metering orifice disc according to claim 7, further
comprising: a second orifice penetrating the second facet and being
defined by a second wall coupling the first and second surfaces,
the second orifice extending along a second orifice axis, and the
second orifice axis being oblique with respect to the second plane
such that an orientation of the second orifice with respect to the
longitudinal axis is defined by a combination of a third
relationship of the second plane with respect to the base plane and
a fourth relationship of the second orifice axis with respect to
the second plane.
11. The metering orifice disc according to claim 10, wherein the
second orifice axis is oblique with respect to the first orifice
axis.
12. The metering orifice disc according to claim 11, wherein the
longitudinal, first orifice, and second orifice axes are
intersecting.
13. The metering orifice disc according to claim 10, wherein the
central portion of the member comprises a third facet extending
parallel to a third plane, the third facet being coupled to the
peripheral portion along a third peripheral segment, and the third
plane being oblique with respect to the base plane.
14. The metering orifice disc according to claim 13, wherein the
third facet is non-penetrated, and the third facet is coupled to at
least one of the first facet along a second central segment and the
second facet along a third central segment.
15. The metering orifice disc according to claim 14, wherein the
third facet is coupled to the first and second facets along the
second and third central segments, respectively.
16. The metering orifice disc according to claim 6, wherein the
first surface and second surface comprise a planar surface
extending away from the seat and oblique to the longitudinal
axis.
17. The metering orifice disc according to claim 6, wherein the
first surface and second surface comprise a planar surface
extending towards the seat and oblique to the longitudinal
axis.
18. The metering orifice disc according to claim 6, wherein the
first orifice has a diameter ranging between approximately 125
microns to approximately 600 microns.
19. A method of forming a metering orifice disc for a fuel
injector, the metering orifice disc including a member including
first and second surfaces extending substantially parallel to a
base plane, the first and second surfaces being spaced along a
longitudinal axis extending orthogonal with respect to the base
plane, the first surface comprising an apex and a perpendicular
height of the apex with respect to the base plane, the method
comprising: forming a first orifice penetrating the member, the
first orifice being defined by a first wall coupling the first and
second surfaces, and the first orifice extending along a first
orifice axis oblique with respect to the longitudinal axis; forming
a first facet extending parallel to a first plane, the first facet
being penetrated by the first orifice, and the first plane being
oblique with respect to the base plane; and ensuring that a
generally direct correlation exists between the height of the apex
and the orientation of the first orifice with respect to the
longitudinal axis.
20. The method according to claim 19, wherein the forming the first
orifice comprises at least one of punching, drilling, shaving, and
coining.
21. The method according to claim 19, wherein the forming the first
facet comprises at least one stamping and punch forming.
22. The method according to claim 19, comprising: forming a second
orifice penetrating the member so provided, the second orifice
being defined by a second wall coupling the first and second
surfaces, and the second orifice extending along a second orifice
axis oblique with respect to the longitudinal axis.
23. The method according to claim 22, wherein the forming the
member so penetrated comprises forming a second facet extending
parallel to a second plane, the second facet being penetrated by
the second orifice, and the second plane being oblique with respect
to the base plane.
24. The method according to claim 23, wherein the forming the
member so penetrated comprises forming a third facet extending
parallel to a third plane, and the third plane being oblique with
respect to the base plane.
25. The method according to claim 24, wherein the forming the
member so penetrated comprises forming the first surface as a
concave surface and forming the second surface as a convex surface.
Description
FIELD OF INVENTION
This invention relates generally to electrically operated fuel
injectors of the type that inject volatile liquid fuel into an
automotive vehicle internal combustion engine, and in particular
the invention relates to a novel thin disc orifice member for such
a fuel injector.
BACKGROUND OF THE INVENTION
It is believed that contemporary fuel injectors must be designed to
accommodate a particular engine, not vice versa. The ability to
meet stringent tailpipe emission standards for mass-produced
automotive vehicles is at least in part attributable to the ability
to assure consistency in both shaping and aiming the injection
spray or stream, e.g., toward intake valve(s) or into a combustion
cylinder. Wall wetting should be avoided.
Because of the large number of different engine models that use
multi-point fuel injectors, a large number of unique injectors are
needed to provide the desired shaping and aiming of the injection
spray or stream for each cylinder of an engine. To accommodate
these demands, fuel injectors have heretofore been designed to
produce straight streams, bent streams, split streams, and
split/bent streams. In fuel injectors utilizing thin disc orifice
members, such injection patterns can be created solely by the
specific design of the thin disc orifice member. This capability
offers the opportunity for meaningful manufacturing economies since
other components of the fuel injector are not necessarily required
to have a unique design for a particular application, i.e. many
other components can be of common design.
Another concern in contemporary fuel injector design is minimizing
the so-called "sac volume." As it is used in this disclosure, sac
volume is defined as a volume downstream of a needle/seat sealing
perimeter and upstream of the orifice hole(s). The practical limit
of dimpling a geometric shaped into an orifice disc pre-conditioned
with straight orifice holes is the depth or altitude of the
geometric shape required to obtain the desired spray angle(s).
Obtaining the larger bend and split spray angles makes the
manufacturing more difficult and increases sac volume at the same
time. At the same time, as the depth or height of the geometry
increases, the amount of individual hole and dimple distortion also
increases. In extreme instances, the disc material may shear
between holes or at creases in the geometrical dimple.
It is believed that known metering orifice disc can be formed in
the following manner. A flat metering disc is initially formed with
an orifice that extends generally perpendicular to the flat
metering orifice disc, i.e., a "perpendicular" orifice. In order to
achieve a bending or split angle, i.e., an angle at which the
orifice is oriented relative to a longitudinal axis of the fuel
injector, the region about the orifice is dimpled such that the
flat metering orifice disc is no, longer generally planar in its
entirety but is now provided with a multi-facetted dimple. As the
metering orifice disc is dimpled, the material of the metering
orifice disc is forced to yield plastically to form the
multi-facetted dimple. The multi-facetted dimple includes at least
two sides extending at a dimpling angle, i.e., the angle at which
the planar surface of the facet on which the orifice is disposed
thereon is oriented relative to the originally flat surface towards
an apex. Since the orifice is located on one of the sides, the
orifice is also oriented at a bending angle .beta.. Because the
orifice originally extends perpendicularly through the flat surface
of the disc, i.e., a "base" plane, a bending angle of the orifice,
subsequent to the dimpling, generally approximates the dimpling
angle. And depending on the physical properties of the material
such as, for example, thickness and yield strength of the material,
it is believed that there is an upper limit to the dimpling angle,
as too great a dimpling angle can cause the material to shear,
rendering the metering orifice disc structurally unsuitable for its
intended purpose.
SUMMARY OF THE INVENTION
The present invention relates to novel forms of thin disc orifice
members that can enhance the ability to meet different and/or more
stringent demands with equivalent or even improved consistency. For
example, certain thin disc orifice members according to the
invention are well suited for engines in which a single fuel
injector is required to direct sprays or stream to one or more
intake valve; and thin disc orifice members according to the
invention can satisfy difficult installations where space for
mounting the fuel injector is severely restricted due to packaging
constraints. It is believed that one of the advantages of the
invention arises because the metering orifices are located in
facetted planar surfaces. This has been found important in
providing enhanced flow stability for proper interaction with
upstream flow geometries internal to the fuel injector. The
presence of a metering orifice in a non-planar surface, such as in
a conical dimple, may not be able to consistently achieve the
degree of enhanced flow stability that is achieved by its
disposition on a facetted planar surface as in the present
invention. The particular shape for the indentation that contains
the facetted planar surfaces having the metering orifices further
characterizes the present invention.
The preferred embodiments of the present invention allow for a
desired targeting of fuel spray. The desired targeting of fuel
spray is one which is similar to a fuel spray targeting generated
by a control case. By virtue of the preferred embodiments, however,
a desired spray targeting similar to the spray targeting of the
control case can be obtained while providing for a fuel injector
that has less sac volume and less material deformation in a
metering orifice disc than that of the control case. Consequently,
it is believed that the present invention provides a better control
of fuel flow and spray angles by virtue of reduced orifice hole
distortion, and reduced likelihood of orifice disc material
shearing.
The present invention provides a fuel injector for spray targeting
fuel. The fuel injector includes a seat, a movable member, and a
metering orifice disc. The seat includes a passage that extends
along a longitudinal axis. The movable member cooperates with the
seat to permit and prevent a flow of fuel through the passage. The
metering orifice disc includes first and second surfaces, a
peripheral portion, a central portion, and a first orifice. The
first surface confronts the seat, and the second surface faces
opposite the first surface. The peripheral portion is with respect
to the longitudinal axis and extends parallel to a base plane,
which is generally orthogonal with respect to the longitudinal
axis. The central portion is also with respect to the longitudinal
axis and is bounded by the peripheral portion. The central portion
includes a first facet that extends parallel to a first plane. The
first facet is coupled to the peripheral portion along a first
peripheral segment, and the first plane is oblique with respect to
the base plane. The first orifice penetrates the first facet and is
defined by a first wall that couples the first and second surfaces.
The first orifice extends along a first orifice axis that is
oblique with respect to the first plane. As such, the orientation
of the first orifice with respect to the longitudinal axis is
defined by a combination of (1) a first relationship of the first
plane with respect to the base plane, and (2) a second relationship
of the first orifice axis with respect to the first plane.
The present invention also provides a metering orifice disc for a
fuel injector. The fuel injector includes a passage that extends
along a longitudinal axis between an inlet and an outlet, a closure
member that reciprocates along the longitudinal axis, and a seat
that is proximate the outlet and cooperates with the closure member
to permit and prevent a flow of fuel through the passage. The
metering orifice disc includes a member and an orifice. The member
includes first and second generally parallel surfaces. The first
surface is adapted to generally confront the valve seat, and the
second surface faces opposite the first surface. The member further
includes a peripheral portion with respect to the longitudinal
axis, and a central portion with respect to the longitudinal axis.
The peripheral portion extends parallel to a base plane, and the
base plane is generally orthogonal with respect to the longitudinal
axis. The central portion is bounded by the peripheral portion and
includes a first facet that extends parallel to a first plane. The
first facet is coupled to the peripheral portion along a first
peripheral segment, and the first plane is oblique with respect to
the base plane. The first orifice penetrates the first facet and is
defined by a first wall coupling the first and second surfaces. The
first orifice extends along a first orifice axis, and the first
orifice axis is oblique with respect to the first plane such that
an orientation of the first orifice with respect to the
longitudinal axis is defined by a combination of (1) a first
relationship of the first plane with respect to the base plane, and
(2) a second relationship of the first orifice axis with respect to
the first plane.
The present invention further provides a method of forming a
metering orifice disc for a fuel injector. The metering orifice
disc includes first and second surfaces that extend substantially
parallel to a base plane and that are spaced along a longitudinal
axis extending orthogonal with respect to the base plane. The
method can be achieved by: forming a first orifice that penetrates
the member; and forming a first facet that extends parallel to a
first plane. The first orifice is defined by a first wall that
couples the first and second surfaces, and the first orifice
extends along a first orifice axis that is oblique with respect to
the longitudinal axis. The first orifice penetrates the first
facet, and the first plane is oblique with respect to the base
plane.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings, which are incorporated herein and
constitute part of this specification, illustrate presently
preferred embodiments of the invention, and, together with the
general description given above and the detailed description given
below, serve to explain features of the invention.
FIG. 1 is a cross-sectional view of a fuel injector according to a
preferred embodiment of the present invention.
FIG. 1A is a close-up cross-sectional view of the outlet end
portion of the fuel injector of FIG. 1.
FIG. 1B is a perspective view of a multi-faceted dimpled metering
orifice disc according to a preferred embodiment as viewed from a
fuel exit side of the fuel injector.
FIG. 2 is fragmentary cross-sectional view of a metering orifice
disc according to a preferred embodiment of the present invention
in an intermediate condition.
FIG. 3 is a fragmentary cross-sectional view of the metering
orifice disc according to the preferred embodiment of the present
invention, as shown in FIG. 2, in a final condition.
FIGS. 4A and 4B illustrate the dimensions of a metering orifice
disc in an initial pre-dimpled configuration to a final dimpled
configuration for a control case in comparative analysis that
achieves a predetermined spray targeting.
FIGS. 4C and 4D illustrate other dimensions of the thin disc of
FIG. 4B.
FIGS. 5A and 5B illustrate a metering orifice disc, prior to
dimpling, that can be used for the preferred embodiments.
FIG. 6 illustrates a comparison between a configuration of a first
preferred embodiment of a metering orifice disc relative to the
control case that achieves the same exemplary spray results.
FIG. 7 illustrates a comparison between a configuration of a second
preferred embodiment of a metering orifice disc relative to the
control case that achieves the same exemplary spray results.
FIG. 8 illustrates a comparison between a configuration of a third
preferred embodiment of a metering orifice disc relative to the
control case that achieves the same exemplary spray results.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)
FIGS. 1 8 illustrate the preferred embodiments. In particular, a
fuel injector 100 includes: a fuel inlet tube 110, an adjustment
tube 112, a filter assembly 114, a coil assembly 118, a coil spring
116, an armature 120, a closure member assembly 122, a non-magnetic
shell 124, a fuel injector overmold 126, a body 128, a body shell
130, a shell overmold 132, a coil overmold 134, a guide member 136
for the closure member assembly 122, a seat 138, and a metering
disc 140. The construction of fuel injector 100 can be of a type
similar to those disclosed in commonly assigned U.S. Pat. Nos.
4,854,024; 5,174,505; and 6,520,421 with respect to details that
are not specifically portrayed in FIGS. 1 and 1A.
FIG. 1A shows the nozzle end of a body 128 of a solenoid operated
fuel injector 100 having a metering orifice disc 140 according to a
preferred embodiment. The nozzle end of fuel injector 100 includes
a guide member 136 and a seat 138, which are disposed axially
interiorly of metering orifice disc 140. The guide member 136, seat
138 and disc 140 can be retained by a suitable technique such as,
for example, forming a retaining lip with a retainer or by welding
the disc 140 to the seat 138 and welding the seat 138 to the body
128.
Seat 138 can include a frustoconical seating surface 138a that
leads from guide member 136 to a central passage 138b of the seat
138 that, in turn, leads to a dimpled central portion 140a of
metering orifice disc 140. Guide member 136 includes a central
guide opening 136a for guiding the axial reciprocation of a sealing
end 122a of a closure member assembly 122 and several
through-openings 136b distributed around opening 136a to provide
for fuel to flow into the fuel sac volume discussed earlier. The
fuel sac volume is the encased volume downstream of the needle
sealing seat perimeter, which is the interface of 122a and 138a,
and upstream of the metering orifices in the area 140a. FIG. 1A
shows the hemispherical sealing end 122a of closure member assembly
122 seated on sealing surface 138a, thus preventing fuel flow
through the fuel injector.
As shown in FIG. 1A, a volume is defined by the first surface of
the metering orifice disc and the sealing end 122a cooperating with
the seat 138 to prevent the flow of fuel. This volume is generally
related to the orientation of the first orifice with respect to the
longitudinal axis. That is, with reference to FIGS. 2 and 3, as the
first orifice 148 is oriented at increasing angle .beta. relative
to axis 200, this volume, also known as the "sac" volume,
increases. Conversely, as the first orifice 148 is oriented at
decreasing angle .beta. relative to the axis 200, the sac volume
decreases.
The metering orifice disc 140, as viewed from outside of the fuel
injector in a perspective view of FIG. 1B, has a generally circular
shape with a circular outer peripheral portion 140b that
circumferentially bounds the central portion 140a that is disposed
axially in the fuel injector.
With reference to FIGS. 2 and 3, the preferred embodiments achieve
an increased bending angle, denoted here as bending angle .theta.,
without an increase in a dimpling angle .lamda. that must be
applied to the work piece. Briefly, the increased bending angle
.theta. can be formed by initially forming an orifice that is
angled to a flat work piece 10 at an orifice angle .alpha., i.e.,
"angled" orifice, relative to a virtual base plane 150 which is
contiguous to at least a portion of disc. Thereafter, the work
piece 10 is deformed to form a multi-facetted dimple 143a at the
same dimpling angle .lamda. as in the conventional dimpled disc. As
shown in FIG. 3, however, the new bending angle .theta. is not
related directly as a function of the dimpling angle .lamda. but is
related as a function of two angles: (1) the orifice angle .alpha.
and (2) the dimpling angle .lamda.. Thus, the increased bending
angle .theta. for spray targeting results from approximately the
sum of the orifice angle .alpha. and the dimpling angle
.theta..
In the preferred embodiments, the central portion 140a of metering
orifice disc 140 includes a multi-faceted dimple 143a that is
bounded by the central portion 140a, as shown in FIG. 1B. The
central portion 140a of metering orifice disc 140 is imperforate
except for the presence of one or more orifices 144 via which fuel
passes through metering orifice disc 140. Any number of orifices
144 in a suitable array about the longitudinal axis 200 can be
configured so that the metering orifice disc 140 can be used for
its intended purpose in metering, atomizing and targeting fuel
spray of a fuel injector. The preferred embodiments include four
such through-orifices 144.sub.I, 144.sub.II, 144.sub.III,
14.sub.IV, and it can be seen in FIG. 1B, that these orifices can
be disposed solely on the planar surfaces of a multi-faceted dimple
142 of the metering orifice disc 140.
Referencing FIGS. 1B and 6, the multi-faceted dimple 142 of one
preferred embodiment includes six generally planar surfaces oblique
to a virtual base plane 150 extending between the peripheral and
central portions of the metering orifice disc 140. The six
generally planar surfaces intersect each other to form various face
line or segments denoted as A, B, C, D, E, F, G, H, I, J, K, L, M,
N, and O (FIG. 6). The orifices can be located on any one of the
facets as long as the facet includes sufficient area for the
orifices to be disposed thereon. In the preferred embodiments, two
orifices are located on a first facet bounded by segments A, B, H,
I, and L, and two other orifices are located on a second facet
bounded by segments D, E, F, G, and H. A third facet bounded by
segments A, E, and K is contiguous to the first and second facets.
A fourth facet bounded by segments J, F, C, I and N is also
contiguous to the first and second facets. A fifth facet bounded by
segments BMC and its mirror image sixth facet bounded by segments
G, J, and O are contiguous to the fourth facet and to either the
first or second facets, respectively. Although the third through
sixth facets, in the preferred embodiments, are not provided with
orifices penetrating through each of the third through sixth
facets, these surfaces can be provided with one or more orifices in
a suitable application, such as, for example, an intake port with
three intake valves.
As provided by the preferred embodiments, the dimpled orifice disc
140 provides for an increase in a spray angle .theta. relative to a
longitudinal axis A--A for each of the orifices without increasing
the angle at which a facet is oriented relative to the base plane
150, i.e., a bending angle .beta. or split angle .lamda. (FIG. 4C).
That is, the preferred embodiments, including the description of
the techniques disclosed herein, allow the metering orifice disc to
maintain the same spray targeting and enhance structural rigidity
by reduction of significant parameters such as the height of the
apex of the dimple with respect to a base plane. And from a
performance standpoint, a smaller sac volume can thereby be
achieved.
Prior to the formation of the first facet 143a, the metering
orifice disc 140 includes first and second surfaces 20, 40 that
extend substantially parallel to a base plane 150. The first and
second surfaces 20 and 40 are spaced along a longitudinal axis 200.
The longitudinal axis 200 extends orthogonally with respect to the
base plane 150, as shown in FIG. 2. Preferably, the first and
second surfaces 20, 40 are spaced apart over a distance of between
75 microns to 300 microns, inclusive of the values thereof.
The preferred embodiments of the metering orifice disc 140 can be
formed by a method as follows. The method includes forming a first
orifice 148 penetrating the first and second surfaces 20, 40,
respectively, and also includes forming a first planar surface or
facet 143a on which the first orifice 148 is disposed thereon such
that the first facet 143a extends generally parallel to a first
plane 152 oblique to the base plane 150. The first orifice 148 is
defined by a first wall 148a that couples the first surface 20 and
the second surface 40, which are now concave and convex,
respectively, as a result of forming the first facet 143a. The
first orifice 148 extends along a first orifice axis 202 oblique
with respect to the longitudinal axis 200. Although the orifice can
be formed of a suitable cross-sectional area such as for example,
square, rectangular, oval or circular, the preferred embodiments
include generally circular orifices having a diameter about 100
microns, and more particularly, about 125 microns. The first
orifice 148 can be formed by a suitable technique or a combination
of such techniques, such as, for example, laser machining, reaming,
punching, drilling, shaving, or coining. Preferably, the first
orifice 148 can be formed by stamping and punch forming such that
when a dimpling tool deforms the work piece 10, a plurality of
planar surfaces oblique to a base plane 150 can be formed. One of
the plurality of the planar surfaces can include first facet
143a.
Thereafter, a second facet 143b can be formed at the same time or
within a short interval of time with the first facet 143a. The
second facet 143b can be generally parallel to a second plane
oblique 154 to the base plane 150 such that the orifices disposed
on the second facet is oblique to the longitudinal axis 200. The
second facet 143b can also be oblique with respect to the first
facet 143a. Additional facets can also be formed for the metering
orifice disc in a similar manner to provide for a dimple with more
than two facets.
In order to quantify the advantages of the preferred embodiments
with respect to metering orifice plate that utilizes straight or
non-angled orifices prior to the formation of facets (i.e., a
control case), comparisons were made with respect to preferred
embodiments that utilize angled orifices prior to the formation of
facets. The control case was a work piece that utilizes orifices
extending perpendicular to the planar surfaces of the work piece,
which is deformed to form a plurality of facets. The metering disc
of the control case was configured so that it provides a desired
fuel spray-targeting pattern under controlled conditions. The test
cases, on the other hand, utilize the preferred embodiments at
various configurations such that these various configurations
permit fuel spray targeting similar to the desired fuel spray
targeting under the controlled conditions. That is, even though the
physical geometry of each of the test cases was different, the fuel
spray targeting of each of the test cases was required to be
generally similar to that of the control case. And as used herein,
spray targeting is defined as one of a bending angle or a split
spray angle relative to the longitudinal axis 200 of a standardized
fluid flowing through the fuel injector of the control case and the
preferred embodiments at controlled operating conditions, such as,
for example, fuel temperature, fuel pressure, flow rate and coil
actuation duration.
A metering orifice disc 14 using perpendicular orifices prior to
dimpling, i.e., a "pre-dimpled" disc, for the control case is shown
in FIG. 4A. The pre-dimpled disc 14 has four orifices 12.sub.I,
12.sub.II, 12.sub.III, and 12.sub.IV located about the geometric
center of the metering orifice disc and arrayed such that each of
the centers of the orifices are located within respective quadrants
I, II, III, and IV for this particular example. Specifically, two
of the orifices, denoted here as orifice 12.sub.I, and 12.sub.IV,
are symmetrical about centerline X.sub.0--X.sub.0. Each of orifices
12.sub.I and 12.sub.IV is located at, respectively, approximately
10 degrees from centerline Y--Y. Orifices 12.sub.II, and 12.sub.III
are also symmetrical about centerline X.sub.0--X.sub.0 and each is
located at approximately 55 degrees from the centerline
Y.sub.0--Y.sub.0. Each of the orifices 12.sub.I, 12.sub.II,
12.sub.III, and 12.sub.IV extends generally perpendicular through
disc 14 such that an axis of each of the orifices is generally
parallel to the longitudinal axis A--A of the fuel injector prior
to being dimpled, and therefore the angle of deviation (i.e.,
orifice angle .alpha.) between the axis of each of the orifices
12.sub.I, 12.sub.II, 12.sub.III, and 12.sub.IV with the
longitudinal axis is about zero degrees.
The metering orifice disc 140 after dimpling, i.e., a
"post-dimpled" metering orifice disc is shown for the control case
in FIG. 4B, as viewed from outside of the fuel injector, as a
multi-facetted dimple 140a. Preferably, the multi-faceted dimple
140a includes six generally planar facets that are oblique to a
base plane 150 extending through the peripheral portion of the
metering orifice disc 140. For comparative purposes, the
multi-faceted dimple 140a is depicted with various dimensions that
reference each of the orifices to various intersecting segments
between the facets, which are used as referential datum for this
comparison. In particular, a first tangent for orifice 12.sub.IV
parallel to facet segment "F" with the distance between the tangent
and the facet segment F being designated as dT.sub.IVF; and a
second tangent for orifice 12.sub.IV parallel to facet segment "G"
with the distance between the tangent and the facet segment G being
designated as dT.sub.IVG. A first tangent for orifice 12.sub.III
parallel to facet segment "H" with the distance between the tangent
and the facet segment H being designated as dT.sub.IIIH; a second
tangent for orifice 12.sub.III, parallel to facet segment "E" with
the distance between the tangent and the facet segment E being
designated as dT.sub.IIIE; and a third tangent for orifice
12.sub.III, parallel to facet segment "D" with the distance between
the tangent and the facet segment D being designated as
dT.sub.IIID. Furthermore, the maximum height "h" of the apex of the
dimple 143a, bending angles .beta., and split angle .lamda., shown
here in FIGS. 4C and 4D, respectively, are also measured. As used
herein, the bending angle .beta., as applied to a multifaceted
dimple, denotes the angle of a dimpled surface with respect to the
base plane 150 that tends to orient a flow of fuel through the
metering orifices asymmetrically with respect to axis
Y.sub.o--Y.sub.o and towards two or more sectors. As also used
herein, the split angle .lamda. denotes the angle of a dimpled
surface with respect to the base plane 150 that tends to orient a
flow of fuel through the metering orifices symmetrically with
respect to axis X.sub.o--X.sub.o (FIG. 4D). The magnitudes of the
parameters defining the multi-faceted dimple 143a are collated in
the row labeled as "CONTROL" in Table I below.
TABLE-US-00001 TABLE I Data of Control Case, First, Second, and
Third Preferred Embodiments IV Height V III "h" of Bending VI I II
Sac Apex of Angle Split VII VIII IX X XI Configura- Angle Volume
Facet "H" .beta. Angle .lamda. dT.sub.IVF dT.sub.IVG dT.sub.IIID
dT.sub.IIIE dT.sub.IIIH tion .alpha. (mm).sup.3 (mm) (degrees)
(degrees) (mm) (mm) (mm) (mm) (mm) CONTROL 0.degree. 0.812.degree.
0.56 21.degree. 16.degree. 0.354 0.393 0.225 0.228 0.097 DISC 1
6.degree. 0.726.degree. 0.491 17.7.degree. 12.8.degree. 0.228
0.284- 0.341 0.268 0.093 DISC 2 8.degree. 0.768.degree. 0.490
17.0.degree. 11.5.degree. 0.224 0.302- 0.418 0.234 0.096 DISC 3
10.degree. 0.696.degree. 0.467 16.4.degree. 10.2.degree. 0.237
0.252 0.400 0.235 0.- 089
FIG. 5A illustrates a "pre-dimpled" metering orifice disc 140 that
can be used for the preferred embodiments. Reference is made with
the close-up view of FIG. 5B, which shows two of the four orifices
as angled orifices extending through the metering orifice disc at
orifice angle .alpha. with respect to the longitudinal axis 200
(FIG. 2) of about six degrees (6.degree.). The disc 140 is deformed
to form a multi-faceted dimple 156, as shown in solid lines in FIG.
6.
FIG. 6 provides a pictorial comparison of a "post-dimpled" first
preferred embodiment (facets depicted as solid lines) 156 with the
multi-facetted dimple 140a of the control case (depicted as dashed
lines). The preferred embodiment of FIG. 6 uses orifices, in the
pre-dimpled metering orifice disc, with an orifice angle .alpha. of
six degrees as measured to the perpendicular axis 200 or its
complementary angle of eighty-four degrees (84.degree.) as measured
to the base plane 150. It should be noted that the particular
configuration of the multi-faceted dimple 156 of FIG. 6 allows the
metering orifice disc 140 to obtain approximately the same spray
targeting as the control case. Further, it can be seen in the row
labeled "Disc 1" of Table I that significant parameters defining
the geometry of various facets of the first preferred embodiment as
compared to the control case are much smaller in magnitude (as
signified by bold notations for each of the parameters in Table I)
for the same spray targeting as the control case. The decreases in
these significant parameters are believed to be advantageous. The
four significant parameters include: the height "h" of apex H; sac
volume, bending angle .beta. and split angle .lamda.. For example,
the sac volume is reduced by approximately 11%; the bending angle
.beta. by 16%; the split angle .lamda. by approximately 20%. And
increases in parameters in columns IX and X relating to a distance
between a tangent of an orifice relative to a facet line are
believed to be advantageous because the orifices are now placed
further away from the respective facet line.
FIG. 7 illustrates a second preferred embodiment of a multi-facet
dimple 158 (depicted as solid lines) in comparison with the dimple
140a of the control case (designated as dashed lines). The
preferred embodiment of FIG. 7 uses orifices, in the pre-dimpled
metering orifice disc, with an orifice angle .alpha. of eight
degrees (8.degree.) as measured to the axis 200 of the pre-dimpled
metering orifice disc or its complementary angle of eighty-two
degrees (82.degree.) as measured to the base plane 150. Similar to
the first preferred embodiment, it can be seen in the row labeled
"Disc 2" that significant parameters defining the geometry of
various facets of the second preferred embodiment as compared to
the control case and the first preferred embodiment are much
smaller in magnitude (as signified by bold notations) for the same
spray targeting as the control case.
FIG. 8 illustrates a third preferred embodiment (depicted as solid
lines) of a multi-facetted dimple 160 in comparison with the dimple
140a of the control case (designated as dashed lines). The
preferred embodiment of FIG. 8 uses orifices, in the pre-dimpled
metering orifice disc, with an orifice angle .alpha. of ten degrees
as measured with respect to the longitudinal axis 200 or its
complementary angle of eighty degrees (80.degree.) as measured to
the base plane 150. It should be noted that the particular
configuration of the multi-faceted dimple 160 of FIG. 8 allows the
metering orifice disc 140 of FIG. 8 to obtain approximately the
same spray targeting as the control case. Similar to the first and
second preferred embodiments, it can be seen in the row labeled
"Disc 3" that significant parameters defining the geometry of
various facets of the third preferred embodiment as compared to the
control case, the first and second preferred embodiments are much
smaller in magnitude (as signified by bold notations) for the same
spray targeting as the control case. Additionally, it should be
noted that a trend can be seen in Table I in that the significant
parameters should be decreased when the angle .alpha. of an orifice
relative to an axis 200 is increased prior to dimpling.
The comparative analysis above is believed to illustrate the
advantages of the present invention in allowing for at least a
reduced sac volume, apex height "h", bending angle .beta. and split
angle .lamda. while maintaining the same spray targeting of a
control case that uses perpendicular orifices in the pre-dimpled
metering orifice disc. Furthermore, by comparisons with a control
case, it can be seen that the preferred embodiments permit
generally the same desired fuel spray targeting previously
achievable with a control case yet with better fuel injector
characteristics such as, for example, sac volume, lower material
distortion or failure of the metering disc during the manufacturing
process. Moreover, it can be seen that the spray angle .theta. of
each of the orifices is now a result of at least two angles
(orifice angle .alpha. and at least one of the bending angle .beta.
and split angle .lamda.) such that extreme cases of orifice
geometry can be manufactured without causing any reduction in
structural integrity of the metering orifice disc 140 while also
reducing the sac volume, the height of the apex and the amount of
dimpling force or stress applied to the metering orifice disc
without impairing the strength or integrity of the metering
disc.
While the present invention has been disclosed with reference to
certain preferred embodiments, numerous modifications, alterations,
and changes to the described embodiments are possible without
departing from the sphere and scope of the present invention, as
defined in the appended claims. Accordingly, it is intended that
the present invention not be limited to the described embodiments,
but that it have the full scope defined by the language of the
following claims, and equivalents thereof.
* * * * *